LAS VEGAS--General Motors' latest concept car is a Cadillac that could get 300 miles on a single tank and has nearly all the eco-friendly features you can think of.

The Provoq--the first concept car to get its premiere at CES--runs on a hydrogen fuel cell and a lithium ion battery, according to GM CEO Rick Wagoner, who unveiled the car during a keynote speech Tuesday at the Consumer Electronics Show here. The car primarily runs on hydrogen, but uses the battery for peak power and storing electricity to extend the range. (The battery gets recharged from a wall socket.)

It is expected to get 300 miles on a tank of hydrogen, and the fuel cell--GM's fifth generation of fuel cells--is half the size of the last one, which increases internal room and storage. On the roof sits a solar panel for running the car's electronics.

To increase aerodynamics, shutters automatically cover up the air vents on the grill at high speeds.

"It will go up to 100 miles an hour and from zero to 60 in 8.5 seconds," Wagoner said.

The idea behind the Provoq is to extend some of the eco-friendly features GM has tinkered with in other concept cars into a luxury car. A shrinking supply of fossil fuels, environmental concerns, and rising demand for cars in emerging nations demand it. Global sales of cars hit 70 million units in 2007 and will grow to 85 million in five years.

Critics have complained that GM concentrates too much on gas guzzlers, while investors have noted that Toyota has grown at GM's expense with its efficient cars.

By 2012, half of the company's cars coming off the production line will be capable of running on either gas or E85, which contains 85 percent ethanol, Wagoner said.

"The automotive industry can no longer almost exclusively rely on oil to supply the world's transportation requirements," he said.

Still, Wagoner admitted in his speech and a meeting with reporters before the speech that finding ethanol now isn't easy. Only around 1,400 stations in the U.S. sell E85, while there are about 170,000 stations that sell gas in the country. GM will have eight types of hybrid cars on the road by the end of the year.

Nonetheless, GM has yet to release some of its fancier concepts such as a plug-in hybrid, and several years ago it killed an all-electric car, the EV1.

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Wagoner also , which GM hopes to roll out in 2010. The Volt runs on batteries that are recharged by a motor that runs on ethanol or gas.

"It has been remarkably difficult" to get ethanol pumps installed, he said during the reporter briefing. "We've been doing more work than I thought we would need to."

The U.S. will likely over time have to switch from corn-based ethanol to cellulosic ethanol made from grasses and wood chips. A lot of research will have to be performed on lithium ion batteries too, he added.

Electronics will also play an increasingly important role in car safety. GM's Onstar service, for instance, will get a new feature called Stolen Vehicle Slowdown, which slows down a car that's been reported stolen.

Onstar already contains a feature that lets police track a car reported stolen with the onboard GPS system. Many times, however, police find the car thieves in the car. Rather than surrender, thieves often try to escape. In a given year, police conduct approximately 30,000 chases that result in 300 deaths.

With Stolen Vehicle Slowdown, after the stolen car is started, police can send a signal that will slow it to a stop. While slowing, a cheery automated voice begins to converse with the thieves.

"This vehicle is being slowed at the request of a law enforcement agency," the voice states. "Please remain inside the vehicle."

A lane departure system, which tells you when you are veering out of your lane, was recently installed in some 2008 Cadillacs.

In the future, GM will try to incorporate sensors and transponders in cars that will communicate with other cars and warn of traffic jams and potentially dangerous situations. Cars will slow automatically if the danger of an accident, unknown to the driver, has become imminent.